A flowery tale

Phytotech, a company based in Monmouth Junction, New Jersey, USA, has come out with a technique to purify water contaminated with radiation. Interestingly, the technique uses sunflowers. It works by soaking up uranium from streams and other water sources near derelict nuclear sites. Phytotech tested the effectiveness of sunflowers in cleaning up water at an abandoned uranium factory in Ashtabula, Ohio, USA. In the test, the company treated the effluent with six-week-old sunflowers growing on floats of hydroponic growth. The floats allowed the roots of the flowers to reach deep into the contaminated water. The results of the trial showed that the pilot plant decontaminated 200,000 litres of waste water, cutting the uranium concentrations from an average of 200 micrograms per litre to below 20 micrograms per litre, the safety limit set by the US federal authorities. The researchers also tested the effectiveness of the method at Chernobyl, working in association with the Institute for Cell Biology and Genetic Engineering in Kiev, Ukraine. The sunflowers soaked up 95 per cent of strontium and caesium in a pool near the stricken reactor ( Environmental Science and Technology , Vol 31, No 11).